Besides the old wooden radios (Zenith multi-band) we used to have in the 40s, I used to build crystal sets as a kid. Some were standard Glena crystal radio sets but at least one was a "foxhole" radio using an old Gellette Blue Blade for a rectifier and a bent safety pin for a cat whisker. The coil was magnet wire on a toilet paper tube. It worked great. Spent many nights listening to Gene Autry's Melody Ranch program among others.

      - Mark